1. Field of the Invention
The present invention relates to work cutting attachments for zigzag sewing machines and more particularly, it relates to such attachments in which the work cutting operation is performed by using the source of drive of the sewing machines.
2. Description of the Prior Art
Heretofore, such cutting attachments have been used, particularly in zigzag sewing machines, to cut the hem of a work fabric while it is hemstitched with various stitches. The previously known cutting attachments are of the type secured to the table of a sewing machine by means of screws. For this reason, therefore, it has been necessary to form individual screw holes in sewing machines. Generally, it is difficult, if not impossible, for the user of sewing machines to provide such screw holes for himself, and in order to use such cutting attachments, the user has to purchase a specific sewing machine having individual screw holes for mounting the cutting attachments. Thus, the versatility of previously known cutting attachments is significantly reduced.
Additionally, when such cutting attachments are used for ordinary zigzag sewing machines, trim or chips produced by the cutting attachment tend to be caught on the presser foot of the sewing machine and to be curled thereby. Thus, work advancement and sewing operation may sometimes be impeded.
In order to eliminate the noted difficulties, the inventor of the present invention has previously proposed a work cutting attachment which may be readily mounted on a zigzag sewing machine and which includes a special presser foot operable to feed a work fabric smoothly without curling a cut trim. The work cutting attachment is shown in U.S. Pat. No. 4,625,663 issued Dec. 2, 1986.
In common construction for sewing machines, the presser foot is pressed against the work feeding mechanism of the sewing machine and therefore, it is required to be movable slightly longitudinally or vertically in accordance with the movement of the feeding mechanism. To this end, in the above U.S. patent, the presser foot is pivotally supported by a support arm secured to a base plate. A fixed blade is mounted on a support plate secured to the base plate so as to cooperate with a vertically movable cutting blade to perform a cutting operation. In such a work cutting attachment, the work cutting position and the sewing position should preferably be located close to each other, so that when the work fabric is cut and sewn, there is no possibility of shifts of the fabric position. However, with the construction of the U.S. patent in which the presser foot and the member for supporting the cutting blade are separately provided, there is a limit in arranging the cutting position close to the sewing position. Also, the construction around the presser foot tends to become complicated. Thus, improvement in these components has still been desired.